I think it's likely now that a computer can react safer than a human in certain conditions (example highway high speed where you need to hit the brakes if xyz modeling is occurring). I mean if you are traveling 90 and the guy in front jams on the brakes, it's likely a computer can jam on the brakes faster than a human even the most focused and best reflexes human let alone an elderly or distracted human.
So if that's an example there are probably a hundred other examples that would also be correct for example if the light turns green (and the intersection is clear your car should go and the car behind should follow and so on), now what happens is one driver out of 10 might not go and will hold up 9 other cars. Likely a chain of computer cars will all move when the light turns green.
Another example if the highway is moving at 75 mph all the cars can move at that safely instead of someone wanting to do 58 mph in the left lane and making it like a scene out of a mad max movie where hundreds of cars need to speed up and slow down and change three lanes because one car is fudging up.
Another example is fitting into a parking space (and not on the lines).
I am just pointing out a few examples that a computer can drive better than the average human and waaaaaaaaaaay better than the 16 year olds and the 91 year olds trying to drive with the rest of the population.
I understand my examples need to have ALL computer cars not a mix of computers and humans. Also maybe it needs to have baby steps like semi automatous first and work up to full automatous.
The question remains what to do with the hundreds of millions of cars that are perfectly ok but don't have self driving.